#include <iostream>
#include <fstream>

using namespace std;


ifstream fin("fact.in");
ofstream fout("fact.out");

int NumberOfZeros(int number) {
    int denominator = 5;
    int numberOfZeros = 0;
    while (denominator <= number) {
        numberOfZeros += number / denominator;
        denominator *= 5;
    }
    return numberOfZeros;
}

int main() {

    int P; // reprezinta numarul de zerouri
    fin >> P;
    
    if (P == 0) {
        fout << 1;
    } else if (P == 1) {
        fout << 5;
    } else {
        int number = 6;
        while (true) {
            int zeros = NumberOfZeros(number);
            if (zeros == P) {
                fout << number;
                return 0;
            }
            if (zeros > P) {
                fout << -1;
                return 0;
            }
            number++;
        }
    }

    fin.close();
    fout.close();

    return 0;
}